Screen filter

ABSTRACT

An apparatus for dispensing a powder-like mixture with a hollow tube for containing the mixture, a porous tip sealing the tube so that the material is dispensed through the tip when it is deformed by being pressed against a substantially unyielding surface and a screen mounted in the tube adjacent the tip for keeping the bulk of the mixture away from the tip and thus preventing leaking of the mixture in the region between the screen and tip when liquid material is drawn into the tip member after the tip is pressed against a wet surface.

SCREEN FILTER BRIEF DESCRIPTION OF THE PRIOR ART AND SUMMARY OF THE INVENTION The invention relates to a method and apparatus for dispensing a powder-like mixture, e.g. for use in removing dirt, stains and the like from materials such as fabrics.

Removing dirt and stains from materials such as fabrics has always been a difficult and tedious chore, and the energies of many people have for years been focused on many attempts to make dirt and stain removal easier. Soap, which has been known and used successfully for many centuries, functions by chemically providing a bridge between oily substances, which keep the dirt lodged in the fabric, and water, so that the dirt and oil can be transferred from the material to wash water which can then be discarded. However, soap has a number of drawbacks including an inability to remove many kinds of stains and similar soiling elements from fabrics, and the necessity for water, which precludes use with many materials which cannot be immersed in water without damage. Synthetic detergents and enzyme active detergents, while capable of removing many more stains than soap and generally more effective in washing, have been generally used with water also.

To remove stains and dirt from fabrics and other materials which cannot be immersed in water, many different spot removers have been developed and suc-' However, it has been discovered that the use of solvents and adsorbents together as a mixture in spot removers and similar products is not nearly as effective as sequential and separate application of the solvent and adsorbent. If the solvent is first applied to the spot and permitted to work before the adsorbent is applied, more effective and more satisfactory removal of spots and stains results.

This approach is more fully discussed in a copending application by the same inventor of this application entitled SOLVENT-ADSORBENT METHOD AND PRODUCT, Ser. No. 869,298 filed Oct. 24, 1969, and the disclosure of this application is hereby explicitly incorporated herein by reference.

It is not known precisely why separate application results in such striking improvement in the effectiveness of spot removal, but it is believed that when the two materials are employed in combination, the adsorbent may prematurely attract the solvent before it has had an opportunity to fully mobilize the spot. Separate application of the solvent and adsorbent also permits enzyme crystals, which become active when they encounter the solvent, to be dispersed in the adsorbent and to remain inactive therein until the enzyme-adsorbent mixture is applied to the stain.

While a variety of ways of carrying out this technique of separately and sequentially applying a solvent and adsorbent for more effective spot and dirt removal can be employed, the preferred technique, as discussed in the above mentioned Miller application Ser. No. 869,298, is sequentially applying the liquid solvent and then the adsorbent material to the spot from separate applicators, such as aerosol cans, roll-on cans, so-called dab-o-matic cans or any other suitable cans. So-called dab-o-matic cans or tubes are particularly effective in dispensing the adsorbent mixture and are also quite effective in dispensing the liquid solvent as well. Such dispensers are well known and are simply a hollow tube for holding the mixture with an open end sealed by a deformable, porous foam tip which, when the tip is deformed by being manually depressed against a substantially unyielding surface with the tube in a roughly vertical position, permits some of the mixture to filter through the tip and be deposited on the surface.

However, when such cans or tubes are used in the spot removing technique described above and the tip of the dab-o-matic can with the adsorbent mixture in it is pressed against the now wetted spot, some of the liquid in the spot is drawn upwards into the tip. Part of this liquid drawn into the tip eventually moves into the interior of the container, especially in the region immediately adjacent the tip, where it cakes the adsorbent mixture into a solid mass and prevents further dispensing of the mixture through the tip.

This difficulty is substantially eliminated according to the invention of this application by mounting a mesh screen in the interior of the container adjacent the tip so that the bulk of the mixture is kept away from the region around the tip which becomes wet and thus caking is substantially eliminated. The screen permits the mixture to filter through it into the region between the screen and the tip and from there through the tip as the tip is periodically deformed.

Many other objects and purposes of the invention will become clear from the following detailed description of the drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 shows a cutaway view of a so-called dab-omatic can with a screen mounted therein adjacent the tip.

FIG. 2 shows a view of the can of FIG. 1 along the line 22.

DETAILED DESCRIPTION OF THE DRAWINGS Reference is now made to FIGS. 1 and 2 which show, respectively, a cutaway view of a so-called dab-o-matic can 20 and a view of can 20 along the line 2-2. As mentioned above such dab-o-matic cans are generally well known and have been successfully employed for dispensing a variety of liquid and powdery products for a variety of uses.

Can 20, in particular, includes a hollow, roughly tubular member 22 which contains the material to be dispensed, in this instance the dry adsorbent mixture, and which is open at one end as shown. Member 22 may be constructed of any suitable material such as plastic and may be of any appropriate thickness. If desired the end of member 22 opposite the open end may be detachable to permit the addition of more of the adsorbent mixture.

A second tubular member 24 is inserted into the open end of member 22 as shown and may be wedge fitted in place or fastened in any other way, e. g. by glue. Member 22 is preferably of plastic and provides a suitable surface to which can be attached the porous, foam tip 26 through which the adsorbent mixture filters as the tip is deformed one or more times by being pressed against a substantially unyielding surface.

Porous, foam tip 26 is fastened to ledge 28 on member 24 by any suitable means such as glue. Tip 26 in this embodiment is hemispheric and is porous enough to permit the adsorbent mixture to be dispensed at a convenient rate which is neither frustratingly slow nor frustratingly fast.

As mentioned briefly above, when nothing is done to prevent it, using a dab-o-matic can such as shown in FIG. 1 to dispense a dry'powderlike material onto a wet surface results in some of the liquid on the surface being drawn up into the tip and this causes caking of the powder-like material, particularly in the region within the container immediately adjacent the tip. This caking eventually prevents further dispensing of the material and the container is thereafter effectively useless.

However, screen 30, which is simply a grid of plastic,

metal or other wires with open spaces therebetween through which the adsorbent or other powder-like material gradually filters, keeps the bulk of the material away from the region immediately adjacent tip 26 where caking is particularly a problem. Screen 30, as shown, is preferably fastened to member 24 and any suitable way of so fastening it to member 24 can be employed. The number of wires comprising screen 30 can, of course, be varied for any given size of screen to permit enough material to filter through screen 30 to provide a sufficient output through porous tip 26 and yet not enough so that caking results in the region between tip 26 and screen 30. A spacing between screen 30 and tip 26 of about one quarter inch has been found to be satisfactory.

As mentioned above, the dry adsorbent mixture in dab-o-matic can 20 is preferably a mixture of a chalky adsorbent powder and enzyme crystals, the mixture being applied to a spot after a solvent is separately applied from a separate container so that the spot is removed in a particularly effective fashion. However, the novel invention of this application is useful for dispensing any relatively dry powder-like material onto surfaces where liquid may be drawn into the tip and cause caking. Many other changes. and modifications in the above described embodiment of the invention can of course be made without departing from the scope of the invention and, accordingly that scope is intended to be limited only by the scope of the appended claims.

What is claimed is: 1. Apparatus for dispensing a powder-like mixture 5 comprising:

a hollow body member for containing said mixture having an open end,

a deformable, porous tip member sealing said open end so that said mixture is dispensed through said tip member when said tip member is deformed by being pressed against a substantially unyielding surface, and a screen mounted in said body member separated from and adjacent said tip member so as to bound a region between said screen and said tip member for permitting amounts of mixture to move through said screen to said tip member, but preventing said mixture from building up in said region between said screen and said tip member to a density which is the sameas the density in the re gions adjacent the side of said screen means remote from said tip and thus preventing caking of said mixture in said region between said screen means and said tip member when liquid material has been drawn into said tip member by being pressed against a surface having liquid material associated therewith.

2. Apparatus as in claim 1 wherein said mixture is comprised of enzyme crystals and a chalky powder.

3. Apparatus as in claim 1 wherein said tip member is comprised of foam.

4. Apparatus as in claim 1 wherein said body member includes a first member having an open end and a second tubular member mounted in the open end of said first member, said screen and said tip member being attached to said second member.

5. In a container for dispensing a powder-like mixture from the interior of said container through a porous tip member when said tip is deformed by being pressed manually against a substantially unyielding surface, the improvement comprising screen means mounted between said interior of said container and separated and adjacent from said tip member so as to bound a region between said screen and said tip member for preventing said mixture from building up in the region between said tip member and said screen means to the same density as in the regions adjacent the side of said screen means remote from said tip member and thus preventing caking of said mixture in said .region between said screen means and said tip member when said surface has associated with it liquid material. 

1. Apparatus for dispensing a powder-like mixture comprising: a hollow body member for containing said mixture having an open end, a deformable, porous tip member sealing said open end so that said mixture is dispensed through said tip member when said tip member is deformed by being pressed against a substantially unyielding surface, and a screen mounted in said body member separated from and adjacent said tip member so as to bound a region between said screen and said tip member for permitting amounts of mixture to move through said screen to said tip member, but preventing said mixture from building up in said region between said screen and said tip member to a density which is the same as the density in the regions adjacent the side of said screen means remote from said tip and thus preventing caking of said mixture in said region between said screen means and said tip member when liquid material has been drawn into said tip member by being pressed against a surface having liquid material associated therewith.
 2. Apparatus as in claim 1 wherein said mixture is comprised of enzyme crystals and a chalky powder.
 3. Apparatus as in claim 1 wherein said tip member is comprised of foam.
 4. Apparatus as in claim 1 wherein said body member includes a first member having an open end and a second tubular member mounted in the open end of said first member, said screen and said tip member being attached to said second member.
 5. In a container for dispensing a powder-like mixture from the interior of said container through a porous tip member when said tip is deformed by being pressed manually against a substantially unyielding surface, the improvement comprising screen means mounted between said interior of said container and separated and adjacent from said tip member so as to bound a region betweeN said screen and said tip member for preventing said mixture from building up in the region between said tip member and said screen means to the same density as in the regions adjacent the side of said screen means remote from said tip member and thus preventing caking of said mixture in said region between said screen means and said tip member when said surface has associated with it liquid material. 